Previously, many types of multi-gap spark plugs have been used to provide an effective means for igniting a gaseous mixture of fuel and air within the chamber of an internal combustion engine. The ignition utilizes a high-voltage electric current to create a spark that facilitates combustion that generates the power to drive the cylinders of the internal combustion engine.
A search of the prior art did not disclose any patents that possess the novelty of the instant invention. However, the following U.S. patents are considered related:
Pat. No.InventorIssued2,136,206DukelowNov. 8, 19374,931,686OakleyJun. 5, 19905,189,333Kagawa et al.Feb. 23, 19935,821,676Atchinson, II et al.Oct. 13, 19987,230,370 B2KatoJun. 12, 20077,812,509 B2Tanaka et al.Oct. 12, 20107,936,117 B2HuangMay 3, 2011
Dukelow in U.S. Pat. No. 2,136,206 teaches a spark plug for an internal combustion engine having an intermediate electrode which is insulated from a shell and a central electrode to provide two spark gaps. Thereby resulting in an operation that is much more efficient than is provided with a spark plug having a single spark.
U.S. Pat. No. 4,931,686 issued to Oakley is for a metal spark plug shell with an L-shaped copper core side electrode secured in an axially extended slot on the metal shell. The side electrode includes an attachment end having a portion with an outer side that is threaded contiguous with the metal shell and another portion adjacent to the end of the shell with a recessed outer side that is unthreaded so as to permit spark plug gapping without breakage of the side electrode. The patent includes a heat-resistant sheath that is located around the inner side of the copper core and that typically spot welded to the shell.
Kagawa et al. in U.S. Pat. No. 5,189,333 discloses a multi-gap spark plug having a metallic shell into which a tubular ceramic insulator is enclosed. A center electrode is enclosed in the insulator together with a plurality of L-shaped outer electrodes. The electrodes have a vertical piece and a lateral piece which depend from the front end of the shell surrounding the insulator. The lateral piece has an inner surface parallel with a front end of the insulator. The distance between the insulator and the outer electrode is from 0.3 mm to 1.2 mm.
Atchinson, II et al. in U.S. Pat. No. 5,821,676 teaches a spark plug which includes a center electrode having a tapered portion with a plurality of ridges formed thereon. The spark plug includes a tapered ground electrode positioned over the center electrode. The tapered center and ground electrodes allow for a spark to propagate from the spark plug to the combustion chamber.
U.S. Pat. No. 7,230,370 issued to Kato is for a spark plug having an insulator, a center electrode and a metal shell surrounding the insulator. A first electrode is grounded into the shell and a metal tip is joined to an inner side face of an end portion opposite the face of the center electrode which permits a first discharge gap. The second ground electrode is bonded to the shell allowing a second discharge gap.
U.S. Pat. No. 7,812,509 issued to Tanaka et al. discloses a spark plug with a body, a center electrode, a ground electrode and injection control side poles. The tip of the ground electrode and the tip of the ejection control side poles are positioned in the same plane perpendicular to the axis of the spark plug. The ground electrode and the injection control side poles are arranged at regular intervals around the center electrode.
For background purposes and as indicative of the art to which the invention is related reference may be made to the remaining U.S. Pat. Nos. 7,952,263 issued to Ireland and 7,936,117 issued to Huang.